The history of the Eastern Orthodox Church is traced back to
Jesus Christ and the
Apostles. The Apostles appointed successors, known as
bishops, and they in turn appointed other bishops in a process known as
Apostolic succession. Over time,
five Patriarchates were established to organize the Christian world, and four of these ancient Patriarchates remain Orthodox today. Orthodox Christianity reached its present form in
Late Antiquity (in the period from the 3rd to the 8th century), when the
Ecumenical Councils were held, doctrinal disputes were resolved, the
Fathers of the Church lived and wrote, and Orthodox worship practices settled into their permanent form (including the liturgies and the major holidays of the Church).

In the early Middle Ages, Orthodox missionaries spread Christianity towards the north, to the
Bulgarians,
Serbs,
Russians and others. Meanwhile, a gradual process of estrangement took place between the four Eastern Patriarchates and the Latin Church of Rome, culminating with the
Great Schism in the 11th century, in which Orthodoxy and the Latin Church (later called the Roman Catholic Church) separated from each other. In the Late Middle Ages, the
Fall of Constantinople brought a large part of the world's Orthodox Christians under Ottoman Turkish rule. Nevertheless, Orthodoxy continued to flourish in
Russia, as well as within the
Ottoman Empire among the latter's Christian subject peoples. As the Ottoman Empire declined in the 19th century and several majority-Orthodox nations regained their independence, they organized a number of new
autocephalous Orthodox churches in Southern and Eastern Europe.

Early Christianity

Apostolic era

Christianity first spread in the predominantly
Greek-speaking eastern half of the
Roman Empire. The
Apostles traveled extensively throughout the empire, establishing communities in major cities and regions, with the first community appearing in
Jerusalem, followed by communities in
Antioch,
Ethiopia and others. Early growth also occurred in the two political centers of
Rome and
Greece, as well as in
Byzantium (initially a minor centre under the Metropolitan of Heraclea, but which later became
Constantinople). Orthodoxy believes in the
apostolic succession that they believe was established by the Apostles in the
New Testament; this played a key role in the communities' view of itself as the preserver of the original Christian tradition. Historically the word
"church" did not mean a building or housing structure (for which Greek-speakers might have used the word "
basilica") but meant a community or gathering of like peoples (see
ekklesia). The earliest
Ecclesiology would posit that the
Eucharistic assembly, under the authority and permission of a
Bishop, is what constitutes a Church. As St.
Ignatius of Antioch said, "Let no man do anything connected with the Church without the bishop. Let that be deemed a proper Eucharist, which is [administered] either by the bishop, or
by one to whom he has entrusted it. Wherever the bishop shall appear, there let the multitude [of the people] also be; even as, wherever Jesus Christ is, there is
the Catholic Church. It is not lawful without the bishop either to baptize or to celebrate
a love-feast."[4]

The original church or community of the East before the
Great Schism comprised:

Patristic Age

Much of the official organizing of the
ecclesiastical structure, clarifying true from false teachings was done by the bishops of the church. Their works are referred to as
Patristics. This tradition of clarification can be seen as established in the saints of the Orthodox Church referred to as the
Apostolic Fathers, bishops themselves established by
apostolic succession. This also continued into the age when the practice of the religion of Christianity became legal (see the Ecumenical Councils).

The early Christians had no way to have a copy of the works that later became the canon and other church works accepted but not canonized. Much of the original church
liturgical services functioned as a means of learning these works. Orthodox Church services today continue to serve this educational function. The issue of collecting the various works of the eastern churches and compiling them into a canon, each being confirmed as authentic text was a long protracted process. Much of this process was motivated by a need to address various heresies. In many instances, heretical groups had themselves begun compiling and disseminating text that they used to validate their positions, positions that were not consistent with the text, history and traditions of the Orthodox faith.

Divine Liturgy

Liturgical services, especially the
Eucharist service, are based on repeating the actions of Jesus ("do this in remembrance of me"), using the bread and wine, and saying his words (known as the words of the institution). The church has the rest of the liturgical ritual being rooted in Jewish
Passover,
Siddur,
Seder, and
synagogue services, including the singing of
hymns (especially the
Psalms) and reading from the Scriptures (
Old and
New Testament). The final uniformity of liturgical services became solidified after the church established a
Biblical canon, being based on the
Apostolic Constitutions and
Clementine literature.

Bible

In the Orthodox view, the Bible represents those texts approved by the church for the purpose of conveying the most important parts of what it already believed. The oldest list of books for the canon is the
Muratorian fragment dating to c. 170 (see also
Chester Beatty Papyri). The oldest complete canon of the Christian Bible was found at
Saint Catherine's Monastery (see
Codex Sinaiticus) and later sold to the British by the Soviets in 1933.[6] Parts of the codex are still considered stolen by the Monastery even today.[6] These texts (as a whole) were not universally considered canonical until the church reviewed, edited, accepted and ratified them in 368 AD (also see the
Soteriology from the Orthodox perspective is achieved not by knowledge of scripture but by being a member of the church or community and cultivating
phronema and
theosis through participation in the church or community.[7][8]